/*
* Copyright (C) 2016-2018 ActionTech.
* based on code by MyCATCopyrightHolder Copyright (c) 2013, OpenCloudDB/MyCAT.
* License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
*/
package com.actiontech.dble.route.parser;

import com.actiontech.dble.route.parser.util.ParseUtil;

/**
 * @author mycat
 */
public final class ManagerParseReload {
    private ManagerParseReload() {
    }

    public static final int OTHER = -1;
    public static final int CONFIG = 1;
    public static final int USER_STAT = 4;
    //public static final int CONFIG_ALL = 5;
    public static final int SQL_SLOW = 6;
    public static final int META_DATA = 7;
    public static final int QUERY_CF = 8;

    public static int parse(String stmt, int offset) {
        int i = offset;
        for (; i < stmt.length(); i++) {
            switch (stmt.charAt(i)) {
                case ' ':
                    continue;
                case '/':
                case '#':
                    i = ParseUtil.comment(stmt, i);
                    continue;
                case '@':
                    return reload2Check(stmt, i);
                default:
                    return OTHER;
            }
        }
        return OTHER;
    }

    static int reload2Check(String stmt, int offset) {
        if (stmt.length() > ++offset && stmt.charAt(offset) == '@' && stmt.length() > ++offset) {
            switch (stmt.charAt(offset)) {
                case 'C':
                case 'c':
                    return reload2CCheck(stmt, offset);
                case 'U':
                case 'u':
                    return reload2UCheck(stmt, offset);
                case 'S':
                case 's':
                    return reload2SCheck(stmt, offset);
                case 'Q':
                case 'q':
                    return reload2QCheck(stmt, offset);
                case 'M':
                case 'm':
                    return reload2MCheck(stmt, offset);
                default:
                    return OTHER;
            }
        }
        return OTHER;
    }

    static boolean isConfig(String stmt, int offset) {
        if (stmt.length() == ++offset)
            return true;

        char c1 = stmt.charAt(offset);
        if ((c1 == ' ') || (c1 == '\t') || (c1 == '\r') || (c1 == '\n') || (c1 == '_') || (c1 == '-'))
            return true;

        return false;
    }

    // RELOAD @@CONFIG
    // Please comply with the specification: offset retain the last position that has been checked.
    static int reload2CCheck(String stmt, int offset) {
        if (stmt.length() > offset + 5) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            if ((c1 == 'O' || c1 == 'o') && (c2 == 'N' || c2 == 'n') && (c3 == 'F' || c3 == 'f') &&
                    (c4 == 'I' || c4 == 'i') && (c5 == 'G' || c5 == 'g')) {
                if (isConfig(stmt, offset)) {
                    return (offset << 8) | CONFIG;
                }
            }
        }
        return OTHER;
    }

    // RELOAD @@USER
    static int reload2UCheck(String stmt, int offset) {
        if (stmt.length() > offset + 3) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            if ((c1 == 'S' || c1 == 's') && (c2 == 'E' || c2 == 'e') && (c3 == 'R' || c3 == 'r')) {
                if (stmt.length() > offset + 5) {
                    char c6 = stmt.charAt(++offset);
                    char c7 = stmt.charAt(++offset);
                    char c8 = stmt.charAt(++offset);
                    char c9 = stmt.charAt(++offset);
                    char c10 = stmt.charAt(++offset);
                    if ((c6 == '_' || c6 == '-') && (c7 == 'S' || c7 == 's') && (c8 == 'T' || c8 == 't') &&
                            (c9 == 'A' || c9 == 'a') && (c10 == 'T' || c10 == 't')) {
                        return USER_STAT;
                    }
                }
                return OTHER;
            }
        }
        return OTHER;
    }

    // RELOAD @@SQL
    static int reload2SCheck(String stmt, int offset) {
        if (stmt.length() > offset + 6) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            char c6 = stmt.charAt(++offset);

            // reload @@sqlslow
            if ((c1 == 'Q' || c1 == 'q') && (c2 == 'L' || c2 == 'l') && (c3 == 's' || c3 == 'S') &&
                    (c4 == 'L' || c4 == 'l') && (c5 == 'O' || c5 == 'o') && (c6 == 'W' || c6 == 'w') &&
                    stmt.length() > ++offset && stmt.charAt(offset) != ' ') {
                return SQL_SLOW;
            }

            return OTHER;
        }
        return OTHER;
    }

    // RELOAD @@METADATA
    static int reload2MCheck(String stmt, int offset) {
        if (stmt.length() > offset + 7) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            char c6 = stmt.charAt(++offset);
            char c7 = stmt.charAt(++offset);

            if ((c1 == 'E' || c1 == 'e') && (c2 == 'T' || c2 == 't') && (c3 == 'A' || c3 == 'a') &&
                    (c4 == 'D' || c4 == 'd') && (c5 == 'A' || c5 == 'a') && (c6 == 'T' || c6 == 't') && (c7 == 'A' || c7 == 'a')) {
                if (ParseUtil.isErrorTail(++offset, stmt)) {
                    return OTHER;
                }
                return META_DATA;
            }
        }
        return OTHER;
    }

    // RELOAD @@QUERY
    static int reload2QCheck(String stmt, int offset) {
        if (stmt.length() > offset + 7) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            char c6 = stmt.charAt(++offset);
            char c7 = stmt.charAt(++offset);

            if ((c1 == 'U' || c1 == 'u') && (c2 == 'E' || c2 == 'e') && (c3 == 'R' || c3 == 'r') &&
                    (c4 == 'Y' || c4 == 'y') && (c5 == '_') && (c6 == 'C' || c6 == 'c') && (c7 == 'F' || c7 == 'f')) {
                if (stmt.length() > ++offset && stmt.charAt(offset) != ' ') {
                    return QUERY_CF;
                }
                return OTHER;
            }
        }
        return OTHER;
    }
}
